The most striking thing about Pauline McLynn is not how glamorous she is compared to her Father Ted character, nor her language -- which at times reaches the most colourful shade of blue -- but her laugh.
Filthy, raucous and easily triggered, it's a laugh which suggests hanging out with McLynn is just as entertaining as watching reruns of the now-classic comedy.
In dowdy Mrs Doyle, housekeeper and companion to the titular priest and his sidekicks Dougal and Jack, McLynn created an iconic comedy character, complete with the "ah go on, go on, go on" catchphrase.
Now McLynn is face-to-face with another iconic comedy character, that of Frank Gallagher in Shameless, played by David Threlfall.
The 47-year-old actress has been cast as Frank's new love interest, the plucky but well-meaning librarian Libby Croaker and -- as her laugh suggests -- she's turned ever so slightly shameless for her new role.
"I get to be someone my own age now and actually somebody's love interest. And I have to get my kit off because it's Shameless and sex with someone else, or something else, comes hand in hand with being on the Chatsworth," she says matter of factly.
The sex scenes are certainly further from Father Ted than Manchester is from Craggy Island, where Mrs Doyle was more likely to make a cake than the beast with two backs, but McLynn has thrown herself into the deed.
"There's a lot of shagging between Frank and Libby, as there is at the beginning of every relationship, and I did get naked. It doesn't bother me that people have clothes and underwear on during sex scenes but if it's a time when they should be naked then they should be naked, so I did get my kit off for the first time in my life . . . well, the first time for money," she says with a cackle.
As well as playing Frank, Threlfall -- whom McLynn refers to affectionately as either "Threlly" or "Mr Threlfall" -- directs certain episodes, including the one in which Libby and Frank sleep together for the first time. She deadpans: "He was great, he talked me through all the shots but I found it very hard to concentrate on my lines with one of the top five actors between my legs." But what does Libby see in Frank, one of television's biggest scoundrels?
McLynn has a fair idea.
"Frank's punching well above his weight here, but clearly he is brilliant in bed so that's one of the things that keeps her there.
"But, also, he's got a family and she really wants one and there's an issue with babies and her, so she lets him off, but as the series goes on she stands up to him. He does try to be a better man but, hey, he's Frank," she says with a shrug.
Things are further complicated by the presence of Libby's mother, Patty, played by Valerie Lilley.
"She's the mother from hell, although sometimes she speaks great wisdom and can be nice to people, just not her daughter. She and Frank have a very fraught relationship. They both want Libby to themselves so there's a bit of a power struggle there," McLynn says.
Surely nothing that happens on the Chatsworth Estate has a happy ending -- especially not when Frank's involved?
"Clearly it's going to be a rocky time," McLynn says. "Left to their own devices they'd be fine, but everyone's pulling at them. His family, her family and clearly she has fallen for a very flawed man, I'm not saying that she's perfect either."
In fact, as should be expected from Shameless -- which is now Channel 4's longest-running drama -- Libby is not the lauded prim and proper librarian but is rather, McLynn reveals, described in the script as "a fetishist's vision of what a librarian should look like". The actress, fresh from the set wearing a tight pencil skirt and cinch belt, her hair curled like a vintage pin-up and her eyes adorned with cat-eye make-up, giggles: "We filmed in a library and the librarians took me aside and said, 'We're delighted you're not a stereotypical librarian, you're a little bit glamorous'."
She doesn't know whether Libby will return for the following series ("I'll be the last to find out probably") but she's enjoying her time on set.
"This is consistently the best thing on television. It has a real style to it, and it has such heart and soul. I have to say, there's nothing else like it and there's nothing that can touch it. It's brilliant and now I have to be in it!"
It might also help her to shake off the Father Ted character which, despite her starring role in Jam And Jerusalem and her prolific novel writing, is still what she is most recognised for.
"I have really fond memories but you know what? Rarely a day goes by when someone doesn't mention it, when I don't get recognised. People mention it so much because they love it. When I'm flicking around and it's on the telly I tune in but I see it as 'them' not 'us' anymore," she says, with a twinge of sadness.
Ten years on, the show's popularity still rages on, with fans holding Father Ted conventions in the locations where the comedy was filmed -- although you won't spot McLynn at one of them.
"Would I go? No, God no! I think I'd come back in a body bag if I went to something like that. You'd be killed with kindness," she says with a laugh. She's even said goodbye to her Mrs Doyle wig, her last remnant of the show.
"Recently, I was back in Dublin and I painted a seven-foot Mrs Doyle angel for a charity campaign. I brought my wig here to the Shameless set and Emma in make-up put it on a block and fluffed it up and it was really strange. It was cathartic. I painted the angel and put the wig on, and she's gone. It kind of was symbolic, I just thought, 'let's let her go'," she says.
The new series of Shameless begins on Tuesday, January 26, on Channel 4 at 10pm